import "./player.css";
import { Engine, type SaveApi } from "./engine";
import { loadTranslator, preferredLanguage } from "./i18n";
import { RUNTIMES } from "./runtimes";
import type { GameData, Manifest, SaveData, ScriptModule } from "./types";

async function getJSON<T>(url: string): Promise<T> {
  const r = await fetch(url, { credentials: "same-origin" });
  if (!r.ok) throw new Error(`${r.status} ${url}`);
  return r.json();
}

function blob(manifest: Manifest, path: string) {
  const f = manifest.files[path];
  if (!f) throw new Error(`в версии нет файла ${path}`);
  return `/api/versions/${manifest.versionId}/files/${f.hash}`;
}

function saveApi<T = SaveData>(versionId: number): SaveApi<T> {
  const base = `/api/versions/${versionId}/saves`;
  return {
    list: () => getJSON(base),
    async get(slot) {
      const r = await fetch(`${base}/${slot}`);
      if (r.status === 404) return null;
      if (!r.ok) throw new Error(`${r.status}`);
      return (await r.json()).data as T;
    },
    async put(slot, title, data) {
      const r = await fetch(`${base}/${slot}`, {
        method: "PUT",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ title, data }),
      });
      if (!r.ok) throw new Error(`${r.status}`);
    },
    async remove(slot) {
      await fetch(`${base}/${slot}`, { method: "DELETE" });
    },
  };
}

export interface PlayerHandle { destroy(): void }

export async function launch(root: HTMLElement, versionId: number, onExit: () => void,
                             onProgress: (text: string) => void): Promise<PlayerHandle> {
  onProgress("Загрузка манифеста");
  const manifest = await getJSON<Manifest>(`/api/versions/${versionId}/manifest`);
  const game = await getJSON<GameData>(blob(manifest, "game.json"));
  onProgress(`Загрузка скриптов (${game.scripts.length})`);
  // ?lang= and ?at= come from the translation editor ("play from here")
  const url = new URLSearchParams(location.search);
  const asked = url.get("lang");
  const lang = asked && (asked === game.sourceLang || game.locales?.[asked]) ? asked : preferredLanguage(game);
  const [modules, tr] = await Promise.all([
    Promise.all(game.scripts.map((s) => getJSON<ScriptModule>(blob(manifest, s)))),
    loadTranslator(game, manifest, lang),
  ]);
  if (game.runtime) {
    const load = RUNTIMES[game.runtime];
    if (!load) throw new Error(`Неизвестная среда исполнения игры: ${game.runtime}`);
    return (await load())({ root, game, manifest, modules, url, tr, onExit, versionId, saveApi });
  }
  const engine = new Engine(root, game, manifest, modules, saveApi(versionId),
                            `pgvn:persistent:${versionId}`, onExit, tr,
                            (code) => loadTranslator(game, manifest, code));
  const at = url.get("at");
  if (at) engine.startAt(at);
  else engine.start();
  return engine;
}